Re: Doomsday Closing Argument

Robin Hanson (
Mon, 31 Aug 1998 11:52:24 -0700

Nick B. writes:
>I think Robins' position can be characterized as follows: He accepts
>what I call the self-indication axiom (SIA) and he thinks that also
>non-observers should be included in the reference class.

I didn't address this second issue in my summary, since I didn't think it central. But since Nick devotes most of his summary to this issue, let me say a few words about it.

The most interesting thing I found in the doomsday argument was the apparent suggestion that we should extend our fundamental state space descriptions to include who we turned out to be in history. While I'm not convinced we need to do this, I tried to explore the idea.

The first order of business here, it seemed to me, was to seek a more physics-oriented approach to this. I want our descriptions of fundamental states to be in terms of things the universe cares about, and not directly in terms abstract features like intelligence.

I tried to construct such an approach, and I admit it may not be completely satisfactory. If a satisfactory approach cannot be found, however, I would rather abandon the entire enterprise of extending standard state desciptions.

Let me emphasize in conclusion that I am not against anthropic reasoning and in fact have a paper which makes central use of it. The doomsday argument goes well beyond anthropic reasoning, and one can reject it without rejecting anthropic reasoning.

Robin Hanson RWJF Health Policy Scholar, Sch. of Public Health 510-643-1884 140 Warren Hall, UC Berkeley, CA 94720-7360 FAX: 510-643-8614